多次为 'T_TEMP' 指定了列 'Credits'

Hibernate: select count(*) as COUNT__ from (select top 100 percent T1.*,T2.Credits FROM MemberInfo T1 LEFT JOIN (SELECT SUM(Credits) Credits,MemberId FROM MemberInfo_Credits GROUP BY MemberId)T2 ON T1.MemberId = T2.MemberId WHERE 1=1) T_TEMP
2015-06-24 10:11:23,186 WARN (org.hibernate.engine.jdbc.spi.SqlExceptionHelper:144) - SQL Error: 8156, SQLState: S1000
2015-06-24 10:11:23,186 ERROR (org.hibernate.engine.jdbc.spi.SqlExceptionHelper:146) - 多次为 'T_TEMP' 指定了列 'Credits'。

你的 T1.* 中也有叫 Credits 的字段吧，和 T2.Credits 重名了。
给后面的加个别名，用不重复的名字。

SELECT SUM(Credits) Credits,MemberId FROM MemberInfo_Credits GROUP BY MemberId
//SUM(Credits)和Credits两者之间是否应该加一个逗号